The present invention generally relates to a fluid conduit and, in particular, relates to a fluid conduit having a two-dimensional serpentine opening therethrough.
A well known fluid flow characteristic of a straight conduit is the formation of a parabolic-shaped velocity front. This is a consequence of the peripheral fluid being reduced along its interface with the inner surface of the conduit. This flow retardation is transferred, with lessening effect with distance, toward the central portion of the fluid. Hence, any given cylindrical band of fluid entering a conduit with a planar front is lengthened due to this phenomena. In chromatography this is generally referred to as band dispersion.
Until recently, the chromatographer was predominantly concerned with band dispersion which occurred within the separation column and, to a lesser extent, the band dispersion in the extra-column connecting conduits. However, recent developments in column technology have forced more attention on the effects of extra-column dispersion and the reduction thereof. Extra-column dispersion can introduce unacceptable band, and subsequently peak, broadening both before and after the separating columns.
In the pre-column conduits band dispersion disrupts the planar front of the sample mixture and results in the sample mixture being injected onto the column in a non-uniform concentration. Band dispersion in post-column conduits, such as conduits between the column and the detector, tend to spread each separated component and, by such spreading, cause separated components to overlap. This overlapping results, for all intents and purposes, in a remixing of the previously separated sample components. Consequently, in modern low dispersion chromatography systems, the band dispersion of extra-column connecting conduits is a major consideration.
In general, one approach to reducing dispersion in a fluid conduit is to make the conduit both short and of a small inside diameter. However, such conduits are quite easily plugged and further they are unnecessarily inconvenient in the arrangement and operation of a chromatographic system.